Credit: KMazur/WireImage

Tammy Lynn Michaels blogged that she was "blindsided" Friday when her ex Melissa Etheridge went to court to formally end their partnership.

On her blog, Michaels, 35, wrote:

i am wondering if it’s an art gentle waves no noise for awhile or maybe gentle voices

and SMACK!!!!!!!!!!!! FILE FOR DIVORCE!!!!!!

even though we both promised

agreed handshook pinkyswore

no filing until after tour in the fall

her broken promises told to me by headlines

i’m raising the kids doing what i can second set of yours

could you stop blind sighting me?

unless it’s another art form you’re working on?

have a good concert.

In a Petition for Dissolution of Domestic Partnership filed in L.A. County Superior Court, Etheridge, 49, sought joint custody of their 3-year-old twins, Johnnie and Miller, and asked that the court not award financial support to Michaels.

She cited irreconciliable difference for the reason of their split.

Etheridge and Michaels became domestic partners in August 2005. They announced their split in April.